A projector includes an discharge lamp which has a first electrode and a second electrode and emits light by generating discharge between the first and second electrodes, and a driving system which supplies power by alternating polarities of the first electrode and the second electrode. The driving system is operable in a restoration mode. The driving system melts surface layers of a tip and a surrounding area of the tip extending from a main body of one of the first and second electrodes, and expands a new tip on a tip area of the main body of the one electrode in the restoration mode.